Prior art about code pattern and code patterns were disclosed in Japanese Invention Patent Application Publication No. 2007-11890, U.S. Patent Application Publication No. US2007/0246547, Taiwanese Patent Application Publication No. 094205159, U.S. Patent Application Publication No. US2003/011164, and U.S. Patent Application Publication No. US2006/0007255.
FIG. 1 shows an example of the conventional code pattern and the conventional code patterns. All of the marks 10a for the conventional code pattern 10 are arranged in a square, and all of the conventional code patterns 10 are arranged together, which are also arranged as a conventional code patterns 1 in a square.
FIG. 2 shows an example of the conventional code pattern arranged in a square. In the conventional code pattern 10 shown as FIG. 2, there are 16 marks for boundary (marked with “●”), and 3 marks for orientation (marked with “▴”), and 13 marks for information (marked with “▪”), so that the ratio of effective marks is 40%, i.e. 13/(16+3+13)=40%.
FIG. 3 shows another example of the conventional code pattern arranged in a square. In the code pattern shown as FIG. 3, there are 7 marks for boundary (marked with “●”), and 9 marks for information (marked with “▪”), so that the ratio of effective mark is 56%, i.e. 9/(7+9)=56%.
In view of the necessity of further improvement on the ratio of effective mark achieved by the conventional coding method of the conventional code pattern, the inventors of the present invention worked hard and proposed a code pattern with a rhombus area distribution, which can effectively improve the ratio of effective marks.